A platelet membrane glycoprotein GPIIb/IIIa (hereinafter abbreviated sa GPIIb/IIIa) belongs to the integrin family which is one of the receptor groups concerned with the adhesion between cells or between cell substrates, and forms a heterodimer on the platelet surface in the presence of Ca.sup.++. It is also called .alpha..sub.IIb .beta..sub.3. By the adhesion of platelets to the injured site of a blood vessel and on stimulation by adenosine 5'-diphosphate (ADP) or thrombin, GPIIb/IIIa undergoes stereostructural changes and binds to a ligand having an RGD (arginine-glycine-aspartic acid) sequence, such as fibrinogen and von Willebrand's factor (GPIIb/IIIa does not bind to these ligands when it is not stimulated), as a result of which the final stage of the transmission of stimulation, namely, platelet aggregation, is induced. Therefore, a pharmaceutical agent (GPIIb/IIIa antagonist) which inhibits the binding of GPIIb/IIIa to these ligands can be a superior antiplatelet agent.
From this viewpoint, there have been already known [[4-[(p-amidino-N-methylbenzamide)acetyl]-o-phenylene]dioxy]diacetic acid (Ro 43-8857), [[1-[N-(p-amidinobenzoyl)-L-tyrosyl]-4-piperidinyl]oxy]-acetic acid (Ro 44-9883) (see Leo Alig et al., Journal of Medicinal Chemistry 1992, Vol. 35 (No.23), 4393-4407), N-(n-butanesulfonyl)-O-(4-(4-piperidinyl)-butyl-(S)-tyrosine (L-700,462; MK-383) (see G. D. Hartmans et al., Journal of Medicinal Chemistry 1992, Vol. 35 (No.24), 4640-4642), (3S, 5S)-5-(4'-amidino-4-biphenyl) oxymethyl-3-[(methoxycarbonyl)methyl]-2-pyrrolidinone (BIBU-52) (see Japanese Patent Unexamined Publication No. 264068/1992) and 4-amidino-4'-[(4-carboxycyclohexyl)aminocarbonyl]biphenyl hydrochloride (see Japanese Patent Unexamined Publication No. 334351/1992).
Yet, none of these are necessarily satisfactory in terms of, for example, efficacy, duration of efficacy, side-effects and possibility of oral administration.
Accordingly, an object of the present invention is to provide a novel compound having more superior GPIIb/IIIa-antagonistic action, a pharmaceutical composition thereof and a GPIIb/IIIa antagonist.